The useful life of a mechanical pencil is often limited by the size of its eraser. One solution is to extend the lifetime of the eraser by including a very large eraser, or a double sided eraser that can be flipped over after one side of the eraser is depleted. See, e.g., U.S. Pat. No. 1,914,753. Unfortunately, it is difficult to incorporate such erasers having extended “lifetimes” into the area of the pencil that is used as an actuator.
Another problem with erasers is that they (unfortunate)y) easily pick up and retain dirt, dust, and other surrounding particles, which can make them visually unappealing and also less capable of cleanly removing a pencil mark. This dirt problem can limit the ability of office supply stores to offer mechanical pencils in “open stock,” i.e., without plastic packaging. Such methods of merchandising are advantageous, potentially increasing purchasing opportunities for the ultimate consumer by facilitating immediate testing of the product by the consumer at the point-of-sale.
This dirt problem can also cause a consumer to have an unattractive and messy looking pencil after it is initially used and/or simply stored in a desk, briefcase, or any other container or area where exposure to dirt occurs. One solution to this dirt problem is to provide a cap that is placed over the eraser. This, however, can be difficult. For example, if the cap is fitted over the eraser only, the cap may not stay in place after the eraser is diminished and changed in shape. If the cap is fitted over the eraser and a corresponding section that holds the eraser, the diameter of the cap may require the end of the mechanical pencil to be enlarged to an excessive degree, which can be unsightly especially in cases where the eraser portion acts as an actuator. In both cases, the increased diameter of the cap relative to the eraser portion can negatively affect the aesthetic of the mechanical pencil. Furthermore, it is entirely too easy to displace and lose such caps.